Washington - The Pentagon's top lawyer on Thursday informed the former Navy SEAL who wrote a forthcoming book describing details of the raid that killed Usama bin Laden that he violated agreements to not divulge military secrets and that as a result the Pentagon is considering taking legal action against him.

The general counsel of the Defense Department, Jeh Johnson, wrote in a letter transmitted to the author that he had signed two nondisclosure agreements with the Navy in 2007 that obliged him to "never divulge" classified information.

Johnson said that after reviewing a copy of the book, No Easy Day, the Pentagon concluded that the author is in "material breach and violation" of the agreements.

Johnson addressed his letter to Mr. "Mark Owen," using quotation marks to signify that that this is the author's pseudonym. His real name is Matt Bissonnette.

Bissonnette referred requests for comment about the letter to his publisher, Penguin Putnam, which was not immediately available.

"I write to formally advise you of your material breach and violation of your agreements, and to inform you that the department is considering pursuing against you, and all those acting in concert with you, all remedies legally available to us in light of this situation," Johnson wrote.

The Pentagon has not revealed how it got a copy of the book, which is scheduled to go on public sale next week.

Johnson wrote that "further public dissemination of your book will aggravate your breach and violation of your agreements."

The Pentagon did not release copies of the nondisclosure agreements that it said Bissonnette had signed in 2007. A spokesman, Army Col. Steve Warren, said they were being withheld because they include the author's real name and his signature.